In my earlier copending application identified above, there is disclosed a method of implanting an intraocular lens wherein the effective width of the lens is reduced for implantation by folding the lens and fastening a flexible retainer about it for insertion and then, when the lens has been implanted in the eye, releasing the retainer to free the lens so that the lens can be unfolded within the eye. Apparatus for folding the lens and a retainer for temporarily securing the lens in the folded configuration are also disclosed. The folded lens can be inserted through a much smaller incision than would otherwise be required. For example, a lens which is the typical 6.5 mm in diameter in the unfolded state has an effective width when singly folded of only about 3.2 mm (measured transversely to the axis of folding).
The fold retaining means or "retainer" disclosed in my earlier application may be formed of a thin, flexible material and can be applied around the lens, like a releasable band. Because of its thinness the retainer does not add substantially to the effective diameter of the folded lens, yet it holds the lens so that the lens can be inserted into the eye through a smaller incision.
Experimentation with intraocular lenses held folded by a retainer of the preferred type illustrated in my earlier application has demonstrated that the retainer functions effectively and that, once applied to a lens, the retainer can satisfactorily be removed and the lens unfolded within the eye. However, a practical difficulty has been encountered in that it has been found difficult, or at least time consuming, to apply the retainer to the folded lens prior to implanting, without considerable practice.
My earlier application also discloses an apparatus which is useful to fold a lens so that a retainer can be tied manually "on site", that is, by the physician prior to implanting it. However, the small size and resiliency of the lens makes the placing and securing of the retainer on the lens relatively slow for someone who has not had previous experience in doing so. Accordingly, that application contemplates that the retainer will often be applied by the lens manufacturer and the lens supplied to the eye surgeon in the folded configuration with the retainer already in place, ready for use.
However, some types of plastic materials used to make such foldable lenses tend gradually to lose their resiliency over a period of time and, if held folded by a restrainer for an indefinitely long period of time, such lenses might tend to become deformed so that they would not fully unfold to the original shape but rather would retain some unwanted curvature from folding. This consideration raised the possibility that a lens held folded by a retainer might not have an adequately long shelf life for distribution in the usual channels. Hence it is desirable to provide a means and method by which a lens which could be folded and secured in folded configuration by the physician or an assistant at the point and time of use, i.e., shortly prior to the actual implant operation. In short, there is a need for a simpler way of retaining a lens in a folded configuration, yet which enables the lens to be readily be unfolded and positioned after it has been inserted in the eye.